Plate-type condenser having condensed-liquid-collecting means

ABSTRACT

A plate-type condenser comprises a row of spaced-apart heat transfer plates defining an alternating series of gaseous passages and cooling liquid passages. Within each gaseous passage is provided a plurality of liquid-collecting means for directing the condensed liquid vertically downwardly along discrete flow passages thereby minimizing contact between the heat transfer plates and the condensed liquid. The liquid-collecting means comprises either an array of inclined projections or recesses formed within the heat transfer plates.

States Patent Inventor Hazime Izeki Suita-shi, Osaka, Japan Appl. No. 800,142 Filed Feb. 18, 1969 Patented Jan. 4, 1972 Assignee Hisaka Works, Ltd.

Osaka, Japan Priorities Feb. 6, 1968 Japan 43/7649;

June 28, 1968, Japan, No. 43/552133; June 28, 1968, Japan, No. 43/55234; Aug. 28, 1968, Japan, No. 43/741572; Aug. 28, 1968, Japan, N0. 43/74673; Sept. 4, 1968, Japan, No. 43/78172 PLATE-TYPE CONDENSER HAVING CONDENSED- LIQUID-COLLECTING MEANS 11 Claims, 27 Drawing Figs.

US. Cl

Int. Cl Field of Search [56] References Cited UNITED STATES PATENTS 2,960,160 1 1/1960 Goodman 165/167 X 3,106,243 10/1963 Knudsen 165/167 2,865,613 12/1958 Egenwall et al. 165/167 2,937,856 5/1960 Thomson 165/167 3,399,708 9/1968 Usher et a1 165/165 X FOREIGN PATENTS 521,285 5/1940 Great Britain 165/166 88,695 3/1937 Sweden 165/167 Primary Examiner-Frederick L. Matteson Assistant E.raminerTheophil W. Streule Attorneys-Robert E. Burns and Emmanuel J. Lobato ABSTRACT: A plate-type condenser comprises a row of spaced-apart heat transfer plates defining an alternating series of gaseous passages and cooling liquid passages. Within each gaseous passage is provided a plurality of liquid-collecting means for directing the condensed liquid vertically downwardly along discrete flow passages thereby minimizing contact between the heat transfer plates and the condensed liquid. The liquid-collecting means comprises either an array of inclined projections or recesses formed within the heat transfer plates.

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Ari exhalation condensing process, wherein a gaseous exhalation is cooled down and condensed into a liquid condition, is often employed in various industrial processes mostly in the chemical industry. This condensation of the gaseous exhalation is usually carried out using a heat exchanger. Among varil ous types of heat exchangers, such ones as a shellandtube type, a spiral type and a lamella type are well known. In case of a heat exchanger used for mutual heat exchange of liquids of different temperatures, a platetype one is generally preferred to the shellandtube one because of its larger coefiicient of heat transfer and excellent heat exchangeability. However the conventional platetype heat exchanger entails many drawbacks as will be mentioned later and lack in sufficient functions which can satisfy the demands of the industrial users.

In the conventional platetype condenser, a plurality of thin metal heattransfer plates are vertically arranged in a mutually and parallelly spaced relation forming corresponding narrow passages therebetween, a gaseous exhalation and a cooling liquid are introduced into alternate passages and an exchange of heat between the gaseous two flows takes place so as to condense the exhalation. However, this condensation system results in fonnation of liquid dews concentrated from the exhalation on the surface of the vertical thin plates. With the advance of condensation of the exhalation, the concentrated dews accordingly grow enough in size to fall down along the surface of the plate due to their own weight. Such falling dews combine with each other and spread over the entire width of the plates and form thin liquid layers covering the entire width of the plates surfaces. Itwill be well understood that the thickness of the liquid layer increases in the downward portion of the plates. On account of the presence of the thus formed liquid layers covering the surface of the thin plates, the plates are insulated from a direct contact with the gaseous exhalation which is to be condensed resulting in lowering of the heat exchangeability of the covered portions of the plates.

The condensing condition of the exhalation by cooling on the plate is classified into a layer state, a drop state and a layerdrop coexisting state. The efficiency of heat exchange, that is the effect of condensation, is dependent upon which of the abovementioned states will take place. For example, exhalation may be condensed over a surface of a metal plate in the form of a successive liquid layer when the surface is maintained in a clean condition while it may be condensed there in the form of mutually isolated liquid drops when the surface is covered with a waterrepellent substance layer. The value of the coefficient of heat transfer in case of the drop condensation is known to be several times larger than that in case of the layer condensation. However, there have been no proposals of 5 such a platctype condensers wherein only the drop condensation takes place.

The conventional platetype condenser is further accompanied with the following drawback. In the mechanical construction of the popular platetype condenser conventionally used, the effective width of the exhalation passage in the vicinity of an exhalation inlet is half as large as that of the passage near the middle portion of the plate. That is, along the whole passage of the exhalation there is a difference in the advancing speed of the exhalation therethrough and such a difference causes a pressure loss during the exhalation transfer. Further, in the mentioned construction of the conventional condenser, the ratio of the effective heat transferring area with respect to the total surface area of the plate is very small, that is, the surface of the plate is partially occupied by portions which do not contribute to the heat transfer. Further trouble is encountered by the difficulty in supplying the exhalation to the condenser in a quantity corresponding to the maximum quantity of the exhalation to be condensed per the effective heat transfer area of the surface.

Moreover, the conventional platetype condenser employs packings in the arrangement of the plurality of passages and the contact of the packing with the introduced exhalation eventually causes degradation of the substance composing the packings and this is liable to happen in case the exhalation contains an organic solvent. Further, direct loading of the high temperature pressure of the exhalation upon the packings accelerates the mentioned degradation and breakage of the gaskets.

A principal object of the present invention is to provide a platetype condenser having a large heat transfer efficiency and exhalation condensability wherein the occupying area of the condensed liquid layer is as decreased as possible.

Another object of the present invention is to provide an improved platetype condenser wherein the heat transfer and exhalation condensability is enhanced by causing turbulences within the flows of the cooling liquid in the introduced exhalation.

A still other object of the present invention is to provide an improved platetype condenser wherein the possible quantity of the exhalation introduced therein is enlarged with effective decrease in the pressure loss in the process of exhalation transfer.

In order to attain the abovedescribed objects of the invention, in a platetype condenser provided with a plurality of narrow passages for cooling liquid and exhalation defined by a plurality of vertically, parallelly and spacedly arranged heat transfer plates and with means for sealing the plates together, the improvement of the invention comprises means for collecting condensed liquid dews. This dewcollecting means comprises a condensed liquidguiding shelf disposed within the exhalation passage defined by the heat transfer plates and a condensed liquid conduit disposed in succession with the guiding shelf. The guiding shelf is disposed within the passage in a downwardly inclined arrangement. In the vicinity of the dewcollecting means, there are located at least one inlet of the exhalation and at least one outlet of the liquid condensed from the exhalation.

The invention will be better understood from the following description, reference being made to the accompanying drawing wherein;

FIGS. 1A and 1B are front views of an embodiment of two kinds of heat transfer plates of the present invention,

FIGS. 2 is a perspective model view for showing passages of liquid condensed from exhalation and of cooling water flowing in between pairs of heat transfer plates, according to the present invention,

FIG. 3A is a perspective view for showing a condensing process of exhalation on a heat transfer plate provided with a dewcollecting means of the invention while FIG. 3B is that on a heat transfer plate not provided with such a dewcollecting means,

FIGS. 4A and 4B are front views of another embodiment of the heat transfer plate of the invention used for defining the exhalation passage and the cooling water passage, respective y.

FIGS. 5A and 5B are front views of still other embodiment of the heat transfer plate of the invention used for defining the exhalation passage and the cooling water passage, respectivey.

FIG. 6A is a front view of still other embodiment of the heat transfer plate of the invention used for defining the exhalation P g FIG. 6B is a crosssectional view of the heat transfer plate taken along a line 6B6B in FIG. 6A,

FIG. 6C is a front view of still other embodiment of the heat transfer plate of the invention used for defining the cooling water passage,

FIG. 6D is a crosssectional view of the heat transfer plate taken along a line 6D-6D in FIG. 6C,

FIG. SE is a perspective enlarged model view for showing a flowing condition of the condensed liquid collecting by a dewcollecting means of the present invention,

FIGS. 7A, 7B, 7C and 7D are enlarged vertical sectional views of several embodiments of the dewcollecting means of the present invention,

FIGS. 8A and 8C are front views of still other embodiments of the heat transfer plate of the invention used for defining the exhalation passage,

FIGS. 88 and 8D are front views of embodiments of the heat transfer plate of the invention used for defining the cooling passage and are used with the plates shown in FIGS. 8A and 8C respectively,

FIG. 9A is an enlarged fragmental front view of another embodiment of the dewcollecting means of the invention,

FIG. 9B is an enlarged fragrnental and crosssectional side view of the dewcollecting means shown in FIG. 9A,

FIG. 9C is a perspective whole view of the dew collectingmeans fragmentally shown in FIGS. 9A and 9B, and

FIGS. 10A and 10B are front views of a pair of heat transfer plates of a conventional platetype condenser.

Referring to FIGS. 1A and 18, two kinds of heat transfer plates used in the present invention are shown. One of the heat transfer plates shown in FIG. 1A is provided with condensing surface In upon which is gaseous medium condenses and the other heat transfer plate shown in FIG. 1B is provided with a cooling surface lb for contacting cooling water. Near the upper brim of the heat transfer plate 1, there is formed a gaseous medium or exhalation inlet 2 while a condensed liquid outlet 3 is formed near the lower brim thereof. The width of the inlet 2 is similar to an effective width of the plate I while the width of the outlet 3 is smaller than the effective width. The gaseous medium or exhalation which is to be liquified is introduced through the inlet 2, advanced downwardly along the surface la while being cooled down to condensation on the surface la and the condensed liquid is discharged out of the passage through the outlet 3. The liquidcollecting or dewcollecting means comprises a plurality of condensed-liquidguiding shelves or obliquely extending projections 4a and a plurality of discrete, condensed liquid flow paths 4b. The guiding shelves 4a are arranged within an effective heat transfer area of the surface la of the plate 1. As shown in FIG. 3A, the guiding shelves or projections 40 are disposed on the surface la of the plate in a downwardly inclined or obliquely extending arrangement. In accordance with the size of the effective heat transfer area on the surface la, the shelves 44 can be arranged both in the form of single column and in the form of a plurality of columns. In every column of the shelves arrangement the downward ends of every shelf are arranged along a single, vertical line so that condensed liquid drop falling down from the end of a shelf in a particular column is prevented from splashing by contact with another shelf in another column. Referring to FIG. 1A again, a gasket 5 a is attached to the brim portions of the plate 1 and the surface area of the surface la encircled by the gasket 5a forms the effective heat transfer surface area. Both the exhalation inlet 2 and the condensed liquid outlet 3 are contained within this heat transfer surface area while a cooling water conduit 6b is located outside of the encirclement by the gasket 5a. The cooling water conduit 6b is sealed by another gasket 5b disposed on the surface la encircling the conduit 6b.

Another transfer plate having a surface lb for defining the cooling water passage is shown in FIG. 18, wherein a exhalation inlet 2b and the condensed liquid outlet 3b are both insulated from the cooling water passage by gaskets 5c and 5d. The surface area encircled by the gasket 5e forms an effective heat transfer surface area. The cooling water is introduced into the passage through a cooling water inlet 6, flows into direction shown with arrows 9a, 9b, 9c and discharged through the cooling water conduit 6b formed through the neighboring heat transfer plate 1. The bulkhead 8 defines the abovementioned flowing path of the cooling water.

Referring to FIG. 2, a relative arrangement of the heat transfer plates shown in FIGS. 1A and 1B in the plate condenser of the invention is shown. In the condenser, the plates having the surface la and the plates having the surface lb are alternately, parallelly and spacedly arranged in a facetoface relationship such that one of the surfaces directs against the backside of the other. The row of heat transfer plates thus defined a plurality of gaseousliquid medium passages for flowing therethrough a gaseous medium to be condensed and a plurality of cooling liquid passages alternately positioned between the gaseousliquid medium passages for flowing therethrough a cooling liquid to effect condensation of the gaseous medium. Thus the exhalation inlets 2, the exhalation passages 2b, the condensed liquid outlets 3 and the condensed liquid passages 3b are respectively connected as shown in the drawing. The positions of the cooling water inlet 6 and the cooling water conduit 6b are different in every corresponding plates. Numbering the plates as No. l to No. 4 from left to right in the drawing, the cooling water passages are fonned in between the plates No. I and No. 2 and plates No. 3 and No. 4

while the gaseousliquid medium or exhalation passage is formed in between the plates No. 2 and No. 3.

Next, the operational function of the condenser having the abovedescribed mechanical construction will be hereinafter explained.

Referring again to FIG. 2, the exhalation to be condensed is supplied to the system through the exhalation inlet 2 of the plate No. l as shown with an arrow 7a in the drawing. Together with this, the cooling water is also supplied to the system through the cooling water inlet 6 of the plate No. 4 as shown with an arrow 7b in the drawing.

The supplied gaseous medium is introduced into the exhalation passage defined by the plates No. 2 and No. 3 passing through the exhalation inlet 2 and the exhalation passage 2b as shown with the arrow 71:. The supplied cooling water is introduced into the cooling water passage defined by the plates No. 3 and No. 4 passing through the cooling water inlet 6 conducted along the flowing path defined by the bulkhead 8 as shown with the arrows 9a, 9b, 9c, discharged therefrom through the cooling water conduit 6b of the plate No. 3, further introduced into the cooling water passage defined by the plates No. l and No. 2 through the cooling water inlet 6 of the plate No. 2, conducted along the flowing path defined by the bulkhead 8 and discharged therefrom through the cooling water conduit 6b of the plate No. l.

During-the abovedescribed flowing process of the gaseous medium and the cooling water, transfer of heat between the gaseous medium and the cooling water is performed through the plates No. 2 and No. 3. By this transfer of heat, the exhalation or gaseous medium is sufi'iciently cooled down and condenses upon the surfaces of the plates No. 2 and No. 3 facing the exhalation passage.

The condensing condition of the exhalation is shown in FIGS. 3A and 3B. The cooled exhalation is deposited and condensed on the surface la in the form of dew drops 10a. In the first stage of the condensation, the dew drops 10a are formed over substantially the entire width of the surface la. With the advance of the condensation process, the dew drops 10a grow in size and begin to flow down along the surface la on account of their own weight. This flowing down of the upper dew drops 10a causes a combination of the upper dew drops 10a with the lower dew drops and thus the combined and grownup dew liquid 10b arrives at an upper surface of a condensed liquid shelf or liquid collector 40 at increased flowing down speed. As the shelf 40 of the illustrated embodiment is disposed relative to the surface In in a downwardly inclined arrangement, the arrived dew liquid flows in a free flow condition obliquely and downwardly along the upper surface of the shelf 40 and further flows down vertically along a discrete flow path from the lower end of the shelf 4a along the surface la as is shown with arrows in the drawing. Because the lower ends of the shelves are aligned as already described, the flowing down liquid is not obstructed by the presence of the downwardly positioned shelves and therefore is smoothly conducted along discrete, vertically extending flow paths to the condensed liquid outlet 3. In the abovedescribed process, there are formed three kinds of thin liquid layers. The first liquid layer b is formed in the vicinity of the upper surface of the shelf 4a on the surface la, the second liquid layer 10c is formed on the upper surface of the shelf 4b and the third, relatively thick liquid layer 10d is formed along the condensed liquid conduit 4b on the surface 1a. However, some portion of the dew liquid falls down from the lower end of each projection or shelf without contacting the surface la, thereby decreasing the detrimental effect on the heat transfer operation and the condensation operation due to the presence of the liquid layer. Further, the occupying ratio of the surface area of the liquid layer M with respect to the whole effective heat transfer surface area is so small that the formation of the liquid layer M plays no significant role in lowering the heat transfer efficiency.

The condensing condition of the exhalation on a heat transfer plate having no shelves such as employed in the present invention is illustrated in FIG. 3B, wherein a liquid layer We is formed on almost the entire width of the plate In and this liquid layer 10c grows into a thick liquid layer in the lower portion of the plate 111. Contrary to the abovementioned liquid layer 4b formed in case of the present invention, the occupying ratio of the surface area of the thickened liquid layer 102 with respect to the whole effective heat transfer surface area is enormously large.

Another embodiment of the heat transfer plate of the present invention is shown in FIGS. 4A and 48, wherein the arrangement of the exhalation inlet 2, the exhalation passage 2b, the condensed liquid outlet 3 and the condensed liquid passage 3b is almost the same as that in the embodiment shown in FIGS. IA and 1B. The plate 1 having a surface lb is provided with a pair of cooling water inlets 46 formed on lower comers thereof and a pair of triangular cooling water outlets 460 formed on upper corners thereof while the plate 1 having condensing surface 1a is provided with four cooling water passages 46b and 46d formed the four corners thereof. In this embodiment, a bulkhead 48 of the plate 1 having the surface 1b, as is shown in FIG. 43, has its upper end connected to the gasket 50 so as to form two separated cooling water passages sandwiching the bulkhead 48. The introduced cooling water thus forms two independent flows as shown with arrows 41 in the drawing. Arrangement of the shelves 40 on the plate 1 having the surface 1a is shown in FIG. 4A which is almost similar to that shown in FIG. 1A with a small modification in the lower part. This modified arrangement of the cooling water passage brings about a considerable decrease the load on a pump for supplying the cooling water to the system together with a remarkable increase in the flow speed of the cooling water, the latter resulting in an enhanced efficiency in heat transfer.

Referring to FIGS. 6A, 6B, 6C, 6D, 7A, 7B, 7C and 7D, still other embodiments of the heat transfer plates of the present invention are shown.

In the embodiment shown in FIGS. 6A and 6B, the condensed liquidguiding shelves 4a of the' foregoing embodiments are replaced by a plurality of condensed liquidguiding recesses 640, the condensed liquidguiding conduits 4b of the foregoing embodiments are replaced by a plurality of condensed liquid conduit recesses 64b and both of the recesses 64a and 64b are formed on the surface 1a of the plate I. In this embodiment, the recesses 64b are formed near both side portions of the surface la and the recesses 64a extend upwardly towards the central portion of the surface while, in case of the embodiment shown in FIGS. 6C and 6D, the recess 64b is formed near the central portion of the surface 10 and the recesses 64a extend upwardly towards the both side portions of the surface 1a. The mentioned recesses 64a and 64b are formed simultaneously on the surface 10 of the plate by a conventional pressing operation. By alternately arranging the plate shown in FIG. 6A and the plate shown in FIG. 6C, the directions of the obliquely formed recesses are put in a crossed condition. This crossed condition of the recesses is crosssectionally shown in FIG. 7A, wherein recesses 64a of the neighboring plates 1 project into the cooling water passage in a mutually contacting condition. These recesses 64a of the neighboring plates 1 may also be put in a spacedapart relation.

Several possible embodiments of the crosssectional profile of the recess 64a illustrated in FIGS. 7A to 7D. Among the illustrated embodiments, the recess 64a of the embodiment shown in FIG. 6C is accompanied with a liquid guide projection 67 disposed along and below the recess 64a. The embodiment shown in FIG. 6D is a modification of the one shown in FIG. 6C. By the presence of such recesses on the surfaces of the plates, the effective heat transfer surface area is increased and a turbulence is created in the flows of the exhalation and the cooling water resulting in the enhancement of the heat transfer effect. The crosssectional profile of the abovementioned recesses to be formed on the plate surfaces is not limited to the embodiments already illustrated.

The dewcollecting means of the present invention can also be given in the form of an intermediate plate having a plurality of condensed-liquidguiding ribs on the surfaces thereof and the plate being inserted in between a pair of heat transfer plates. Such an embodiment of the dewcollecting means of the present invention is illustrated in FIGS. 9A, 9B and 9C, wherein an intermediate plate 91 is located within an exhalation passage V defined by a pair of heat transfer plates la and lb. The intermediate plate 91 is provided with a plurality of condensedliquidguiding ribs disposed on both major surfaces thereof. The intermediate plate 91 is also provided with a exhalation inlet 92, the condensed liquid outlet 93, the cooling water inlet 96a and the cooling water outlet 96b, all of which are located therethrough corresponding to those of the heat transfer plates la and 1b. As shown in FIG. 9A, a plurality of guiding ribs 94a are disposed on both surfaces of the intermediate plate 91 in a downwardly inclined arrangement. The crosssectional arrangement of the ribs 940 is shown in FIG. 9B, wherein the ribs 94a is formed by making cuts on the surface of the plate 91 and bending out the cut portion in a direction substantially perpendicular to the surface thereof. In this bending, the vertically neighboring ribs are projected in opposite directions and, in a combined arrangement with the heat transfer plates 1a and 1b sandwiching the intermediate plate 91, the projected ends of the ribs 94a contact the corresponding surfaces of the plates la and lb. Bending out of the ribs 94 remains corresponding apertures 95 on the surface of the plate 91. The combined arrangement of the intermediate plate 91 with the heat transfer plates is shown in FIG. 9C, wherein the plates 91, are shown in a condition spaced apart from each other although, in actual installation, they are combined in such a manner that the projected ends of the guiding ribs 94a contact the corresponding surfaces of the plates. On account of the presence of the apertures 95, the gaseous exhalation advancing downwardly along one side surface of the plate 91 is conducted, upon contact with the ribs 94a, into another side surface of the plate 91 through the apertures 95. That is, the exhalation may be maintained within the exhalation passage V for longer time and this results in the enhanced condensation effect. Further, the intermediate plate 91 forms a reinforcement for the combination of the plates 1.

In the embodiment shown in FIG. 9B, the projections 97 of the plates 1 defining the cooling water passage W are put in mutual contact for the purpose of reinforcement. In this contacting arrangement, the descending direction of the downwardly inclined projection 97 of one plate 1 is opposite to that of the other. In this arrangement, both projections 97 contact to each other at their crossing point resulting in an effective control upon the flow of the cooling water. Because the crosssectional surface area of the exhalation passage V is increased by the presence of the intermediate plate 91, the dimensions of the exhalation inlets and the condensed liquid passage have to be enlarged accordingly.

The already described mechanical constructions of various modified embodiments of the dewcollecting means of the invention may be employed in the construction of a platetype condenser either independently or in suitable combination in accordance with demands in the actual use of the condenser. The objectives of the present invention can be attained by collecting the falling down condensed dew drops at suitable positions on the surface of the heat transfer plate and conducting the collected mass of the condensed liquid towards a discharging conduit in the form of more than one defined and controlled liquid flow. The mechanical assembly for carrying out the above-mentioned process is called a dew-collecting means as a whole.

Referring to FIGS. 10A and 108, an example of the conventional plate-type condenser is shown. In the mechanical construction of the illustrated condenser, the effective width La in the vicinity Xa of an exhalation inlet 153 is half as large as the width Lb of the passage near the middle portion Ya of the plate. That is, along the whole passage of the gaseous exhalation, there is a difference in the advancing speed of the exhalation therethrough and such difference is accompanied by a pressure loss. Further, in the mentioned construction of the conventional condenser, the ration of the effective heat transferring area with respect to the total surface area of the plate is very small, that is the surface of the plate is partially occupied by portions which do not contribute to the heat transfer. Further trouble was caused by a difficulty in supplying the exhalation to the condenser whose quantity is enough to correspond to the maximum quantity of the exhalation to be condensed per the effective heat transfer area of the surface.

Some improvements for eliminating the above-described drawbacks of the conventional plate-type condenser are illustrated in FIGS. A, 58, 8A, 8B, 8C and 8D.

In the embodiment shown in FIG. 5A, the heat transfer plate 1 having the surface In is provided with an exhalation inlet 52 formed within the area of the surface la encircled by the gasket 50 occupying almost the entire width of the encircled surface area. The exhalation inlet 52 is reinforced by a supporting member 54 vertically disposed therein.

In the embodiment shown in FIGS. 8A and 8B, the heat transfer plate 1 having the surface In is provided with an exhalation inlet 82 formed within the area of the surface la encircled by the gasket 5a occupying almost the entire vertical length of the encircled area. In contrast to the embodiment shown in FIGS. 5A and 5B, the exhalation inlet 82 of the present embodiment extends vertically. Under the inlet 82, a rectangular condensed liquid outlet 83 is formed being isolated from the inlet 82 by a bulkhead 89 disposed therebetween, The right end of the bulkhead 89 in the drawing is adequately spaced from the inner surface of the gasket 5a.

In both of the above embodiments, the width of the exhalation inlet is the same as that of the effective heat transfer surface area. Consequently, no pressure loss is created in gaseous exhalation introduced into the exhalation passage and the introduced exhalation can be spread over entire width of the surface 10, conducted adequately by the condensed-liquidguiding shelves, and condensed and deposited over entire width of the effective heat transfer surface area. With the advance of the condensation, the condensed dew drops grow enough to fall down by their own weight and the falling dew drops are combined with each other. The combined mass of the condensed liquid flows along the guiding shelves and is discharged out of the system through the liquid outlet 83. The exhalation passage 82b, the condensed liquid passage 8312, the cooling water inlet 86a and the cooling water outlet 86b are I formed through the plate having the surface 1b corresponding to those formed on the plate having the surface la. Particularly, the cooling water inlet 86a and the outlet 86b are formed on the plate having the surface lb in such a manner that the cooling water is advanced downwardly from the former to the latter except for along the side portion of the plate surface 1b.

In the embodiment shown in FIGS. 8C and 8D, the exhalation inlet 85 and the condensed liquid outlet 87 are located on opposite corners and the dimensions of the former are larger than those of the latter.

An example of the result of the actual use of the plate-type condenser having the dew-collecting means of the invention will hereinafter be explained.

The heat transfer plates shown in FIGS. 1A, 1B, 2 and 3A were used in this example. Four heat transfer plates made of 6.4 copper and having a width of 5 cm. a height of 50 cm. and a thickness of 0.1 cm. were prepared. The effective heat transfer surface area was of 47x38 cm. (The total effective heat transfer surface area was of 0.73 m." and the exhalation side cross-sectional surface area was of 0.l 0.004 m.) The condensed-liquid-guiding shelf was L-shaped in its cross section, wherein both branch of the section was of 0.5 cm. the thickness was of 0.02 cm. and the length was of 6 cm. On every heat transfer plate 1 having the surfaces 1a, 48 shelves were disposed with inclinations of 45. Exhalation was supplied to the system from a supply source 20 meters apart from the system with a supplying rate of 130 kg./hour and was drained at a position just before the exhalation inlet 2. The ordinary water for general industrial use was used as the cooling water. The calculation of the percent heat transfer was made using the following equations.

K=qs/ATm where, K =Percent heat transfer in K cal./m. hr. C.

qs=Thermal load in K cal./m. hr.

ATm =Logarithmic mean temperature difference C.

n A Tm 1n A T 2 A T 3 ATz=Ts T w W0 where,

T; =Temperature of exhalation condensation in C.

T =Temperature in the vicinity of the cooling water outlet in C.

T Temperature in the vicinity of the cooling water inlet in C.

Comparing the thermal load in case of the condenser of the invention with that in case of the conventional condenser, the former showed a 26.5 percent increase over the latter at the condensation temperature of about 97 C. 39 percent increase at about C. and percent increase at about 65 C. without regard to the flow speed of the cooling water. The lower was the condensation temperature, the larger was the degree of increase in the thermal load.

With respect to the effect of the exhalation pressure, provided that the flow speed of the cooling water was constant and the temperature of the water in the vicinity of the cooling water inlet was of 20 C., the smaller was the exhalation pressure, the smaller was the thermal load, that is the smaller was the amount of the condensed liquid. Further, a reduction in the exhalation pressure resulted in a smaller number of the gaseous exhalation molecules smashing into the surface of the heat transfer plate. This caused longer intervals between respective falling down phenomena of the condensed liquid and the discharge of the condensed liquid from the system was slowed down. Thus, reduction in the exhalation pressure led to a reduction in the amount of condensation of the gaseous exhalation.

In case of the conventional condenser having no dew collecting means, the percent heat transfer was of 1,100 K cal./m. hr. C. with the cooling water flow speed of 0.6 meters/sec and the condensation temperature of C. while, in case of the condenser of the present invention, it was of 1,550 K cal./m. hr.C. under the same situation. This means that the employment of the dew-collecting means of the present invention brought about a 41 percent increase in the value of the percent heat transfer with only 5.5 percent increase in the effective heat transfer surface area due to the installation of the condensed-liquid-collecting shelves of the invention.

While the invention has been described in certain embodiments thereof, it is to be understood that various changes and modifications may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. In a plate-type condenser having a plurality of heat transfer plates axially spaced apart in face-to-face relationship, means including said heat transfer plates defining a plurality of first passages for circulating a gaseous substance to be at least partially condensed into a liquid through indirect heat exchange with a cooling liquid and a plurality of second passages alternately positioned with respect to said first passages for circulating a cooling liquid, sealing means for sealing said first and second passages from each other, an improvement comprising: a plurality of liquid collectors for collecting liquid condensed from said gaseous substance provided on surfaces of preselected ones of said heat transfer plates facing said first passages, said liquid collectors on each said surface being inclined downwardly and being arranged in at least one group wherein liquid collectors within each group are substantially parallel to each other and define a plurality of liquid guide paths on said surfaces, and wherein said liquid collectors within each group are arranged in vertical alignment and wherein downward terminations of said collectors in respective vertical alignments are aligned substantially along a single, vertical straight line defining a free-fall vertical flow path for the condensed liquid.

2. An improvement according to claim 1, wherein said liquid collectors comprise guide shelves.

3. An improvement according to claim 1, wherein said liquid collectors comprise elongated projections.

4. An improvement according to claim 1, wherein said liquid collectors comprise means defining elongated recesses.

5. In a platetype condenser having a plurality of heat transfer plates axially spaced apart in faceto-face relationship, means including said heat transfer plates defining a plurality of first passages for circulating a gaseous substance to be at least partially condensed into a liquid through indirect heat exchange with a cooling medium and a plurality of second passages for circulating a cooling medium, a plurality of intermediate plates positioned between pairs of said heat transfer plates comprising portions of said first passages, and sealing means for sealing said first and second passages from each other, an improvement comprising: a plurality of liquid collectors for collecting liquid condensed from said gaseous substance provided on both surfaces of said intermediate plates, said liquid collectors on each said surface being inclined downwardly and being arranged in at least one group wherein liquid collectors within each group are substantially parallel to each other and define a plurality of guide paths on said both surfaces, and wherein said liquid collectors within each group iii are arranged in vertical alignment and wherein downward terminations of said collectors in respective vertical alignments are aligned substantially along a single, vertical straight line defining a freefall vertical flow path for the condensed liquid.

6. An improvement according to claim 5, wherein said liquid collectors comprise guide shelves.

7. An improvement according to claim 5, wherein said liquid collectors comprise elongated projections.

8. An improvement according to claim 5, wherein said liquid collectors comprise means defining elongated recesses.

9. In a condenser operable to effect condensation of a circulating gaseous medium into a liquid medium through indirect heat exchange with a circulating cooling liquid; a row of heat transfer plates axially spaced apart in facetoface relationship; means including said heat transfer plates defining gaseousliquid medium passageways and cooling liquid passageways alternately spaced apart with respect to each other along said row of heat transfer plates; and means disposed within each said gaseousliquid medium passageway defining at least one group of downwardly inclined flow paths each terminating at its lowermost end in a common, continuously vertically extending freefall flow path for directing the condensed, liquid medium formed by condensation of the gaseous medium towards the lower end of the condenser.

10. A condenser according to claim 9; wherein each said group of downwardly inclined flow paths comprises a plurality of vertically aligned projections projecting outwardly into each said gaseousliquid medium passageway, and wherein each projection in each said group of vertically aligned projectrons ob iquely extends towards said lower end of the condenser to direct condensed, liquid medium into a common vertical flow path thereby defining one of said common, continuously vertically extending flow paths.

11. A condenser according to claim 9; wherein each said group of downwardly inclined flow paths comprises means defining a plurality of obliquely extending grooves in the heat transfer plates comprising part of said gaseousliquid medium passageway, and wherein said grooves are disposed in vertically aligned columns and each groove obliquely extends toward said lower end of the condenser to direct condensed, liquid medium into a common vertical flow path thereby defining one of said common, continuously vertically extending flow paths. 

1. In a plate-type condenser having a plurality of heat transfer plates axially spaced apart in face-to-face relationship, means including said heat transfer plates defining a plurality of first passages for circulating a gaseous substance to be at least partially condensed into a liquid through indirect heat exchange with a cooling liquid and a plurality of second passages alternately positioned with respect to said first passages for circulating a cooling liquid, sealing means for sealing said first and second passages from each other, an improvement comprising: a plurality of liquid collectors for collecting liquid condensed from said gaseous substance provided on surfaces of preselected ones of said heat transfer plates facing said first passages, said liquid collectors on each said surface being inclined downwardly and being arranged in at least one group wherein liquid collectors within each group are substantially parallel to each other and define a plurality of liquid guide paths on said surfaces, and wherein said liquid collectors within each group are arranged in vertical alignment and wherein downward terminations of said collectors in respective vertical alignments are aligned substantially along a single, vertical straight line defining a free-fall vertical flow path for the condensed liquid.
 2. An improvement according to claim 1, wherein said liquid collectors comprise guide shelves.
 3. An improvement according to claim 1, wherein said liquid collectors comprise elongated projections.
 4. An improvement according to claim 1, wherein said liquid collectors comprise means defining elongated recesses.
 5. In a plate-type condenser having a plurality of heat transfer plates axially spaced apart in face-to-face relationship, means including said heat transfer plates defining a plurality of first passages for circulating a gaseous substance to be at least partially condensed into a liquid through indirect heat exchange with a cooling medium and a plurality of second passages for circulating a cooling medium, a plurality of intermediate plates positioned between pairs of said heat transfer plates comprising portions of said first passages, and sealing means for sealing said first and second passages from each other, an improvement comprising: a plurality of liquid collectors for collecting liquid condensed from said gaseous substance provided on both surfaces of said intermediate plates, said liquid collectors on each said surface being inclined downwardly and being arranged in at least one group wherein liquid collectors within each group are substantially parallel to each other and define a plurality of guide paths on said both surfaces, and wherein said liquid collectors within each group are arranged in vertical alignment and wherein downward terminations of said collectors in respective vertical alignments are aligned substantially along a single, vertical straight line defining a free-fall vertical flow path for the condensed liquid.
 6. An improvement according to claim 5, wherein said liquid collectors comprise guide shelves.
 7. An improvement according to claim 5, wherein said liquid collectors comprise elongated projections.
 8. An improvement according to claim 5, wherein said liquid collectors comprise means defining elongated recesses.
 9. In a condenser operable to effect condensation of a circulating gaseous medium into a liquid medium through indirect heat exchange with a circulating cooling liquid; a row of heat transfer plates axially spaced apart in face-to-face relationship; means including said heat transfer plates defining gaseous-liquid medium passageways and cooling liquid passageways alternately spaced apart with respect to each other along said row of heat transfer plates; and means disposed within each said gaseous-liquid medium passageway defining at least one group of downwardly inclined Flow paths each terminating at its lowermost end in a common, continuously vertically extending free-fall flow path for directing the condensed, liquid medium formed by condensation of the gaseous medium towards the lower end of the condenser.
 10. A condenser according to claim 9; wherein each said group of downwardly inclined flow paths comprises a plurality of vertically aligned projections projecting outwardly into each said gaseous-liquid medium passageway, and wherein each projection in each said group of vertically aligned projections obliquely extends towards said lower end of the condenser to direct condensed, liquid medium into a common vertical flow path thereby defining one of said common, continuously vertically extending flow paths.
 11. A condenser according to claim 9; wherein each said group of downwardly inclined flow paths comprises means defining a plurality of obliquely extending grooves in the heat transfer plates comprising part of said gaseous-liquid medium passageway, and wherein said grooves are disposed in vertically aligned columns and each groove obliquely extends toward said lower end of the condenser to direct condensed, liquid medium into a common vertical flow path thereby defining one of said common, continuously vertically extending flow paths. 